The VU Meter works and has more or less been validated. I need to make a few more measurements but I’m fairly confident in the circuit at this point. Next step is to add a peak detector to the input and stabilize the display a bit. It flickers too much…

Last night we built a fully functional prototype of the circuit and it worked without any hitches. We limited the number of LEDs for testing; only 30 LEDs were used for output display versus the planned 50. We still need to properly configure the input by adding an amplifier stage and buffer. Some revisions were made to the design to make it easier to print. The traces were again widened and the ground plane was touched up. These images will be included in the next post, which will come when we finalize and have the proto circuit working to music. We are still debating the final look of the actual display and have several different versions. Each version has its place in a different environment. I will try to include some of these sketches in the upcoming photo dump.

I made a few minor tweaks to the board. The most notable change is reducing the number of capacitors and using two different types (ceramic and tantalum) with different capacitances. I also rerouted traces to make the printing and populating process easier on myself. Components will be ordered later today.

I was finally able to give some attention to the VU Meter discussed back in January. The concept is based around the LM3916 chip produced by National Semiconductors. I still have to review the circuit and have another set of eyes sign off on it, but I’m fairly happy with how it stands. The circuit is designed to drive 10 5-LED arrays. The final package for everything is still being discussed but we (Adrian and I) are leaning towards a horizontally mounted wall display. One of the ideas that we are partial to is integrating RGB LEDs to produce a smooth fade of color from one end to the other. Concept sketches to come. For now enjoy some schematics and board layouts!

The shell of the bot was the main the thing to come out of this summer. Life and work kept me busy and the amount of time I was able dedicate to this project was limited. The shell of Wheatley began as a 10.5″ dodgeball and has been fiberglassed. The next stage is to bondo the shell to smooth out the inconsistencies. After that is complete, which may be several weeks away, the shell will be cut and all of the holes and detailing will be focused on. I’ll try to get more material for everyone soon!

A lot of progress has been made on this project since my last post. The designs I included before do not represent, in any way, the finalized design. I’ve begun to collect all of the parts and will begin building this week. Cost is roughly $300-$500.

The design has gone through far too many revisions at this point, but this is important because of the complexity of the build. The mechanics are almost entirely defined with the exception of a few dimensions. Because this whole build is being turned into a tutorial for the community to work from everything has to be transferred to SolidWorks (work-in-progress). I’m partial to the idea that everything is defined so that anyone can follow along. For me this mainly means “I bought this piece here”, “this is exactly what I did to it”, and to be careful of including ”magic” steps. As a result of building this for the community to participate in I’ve also designed around what tools an average DIYer has access to. This limits the build to a small extent because precise pieces cannot be milled or turned. These constraints have also made the design process a lot of fun. It is a big puzzle that is now being assembled.